Camshaft adjusters are used in internal combustion engines to vary the control times of the combustion chamber valves, in order to variably shape the phase relation between a crankshaft and a camshaft in a defined angle range between a maximum advanced position and a maximum retarded position. Adapting the control times to the current load and rotational speed reduces the fuel consumption and emissions. For this purpose, camshaft adjusters are integrated into a drivetrain by which torque is transferred from the crankshaft to the camshaft. This drivetrain can be constructed, for example, as a belt, chain, or gearwheel drive.
In a hydraulic camshaft adjuster, the driven element and the drive element form one or more pairs of mutually interacting pressure chambers that can be loaded with hydraulic medium. The drive element and the driven element are in a coaxial arrangement. By filling and emptying individual pressure chambers, a relative movement between the drive element and the driven element is generated. A spring arranged to provide a rotating effect between the drive element and the driven element forces the drive element relative to the driven element in a preferred direction. This preferred direction can be in the same or opposite direction as the rotation.
One construction of the hydraulic camshaft adjuster is the vane-cell adjuster. The vane-cell adjuster has a stator, a rotor, and a drive wheel with external teeth. The rotor is constructed as a driven element usually so that it can be connected locked in rotation with the camshaft. The drive element includes the stator and the drive wheel. The stator and the drive wheel are connected locked in rotation with each other or are alternatively constructed integrally with each other. The rotor is arranged coaxial to the stator and inside of the stator. The rotor and the stator form mutually interacting oil chambers with their radially extending vanes and these chambers can be charged by oil pressure and allow a relative rotation between the stator and the rotor. The vanes are constructed either integrally with the rotor or the stator or are arranged as “nested vanes” in grooves provided for this reason in the rotor or the stator. The vane-cell adjusters also have various sealing covers. The stator and the sealing covers are secured with each other by threaded connections.
Another construction of the hydraulic camshaft adjuster is the axial piston adjuster. Here, a displacement element is moved axially by oil pressure, which generates a relative rotation between a drive element and a driven element using helical gearing.
Another construction of a camshaft adjuster is the electromechanical camshaft adjuster that has triple-shaft gearing (for example, planetary gearing). Here, one of the shafts forms the drive element and a second shaft forms the driven element. By means of the third shaft, rotational energy can be fed to the system or discharged from the system by a control device, for example, an electric motor or a brake. A spring can also be arranged, which supports or restores the relative rotation between the drive element and the driven element.
EP 1 571 301 A1 shows a camshaft adjusting arrangement, wherein different power sources for adjustments are provided for two camshafts.
DE 10 2010 000 047 A1 shows a valve control device with a drive rotor that turns with a crankshaft, a driven rotor that turns with a camshaft, a planet gear that performs a planetary motion for adjusting the rotational phase between the camshaft and the crankshaft, a motor shaft that turns for controlling the planetary motion, a cylindrical planet gear carrier that carries the planet gear and is connected to the motor shaft such that the planet gear performs a planetary motion, and a lubricating device. The lubricating device has a feed opening that opens on a side surface of the second rotor axially opposite the planet gear carrier. The feed opening extends past an outer bearing surface and an inner connection surface. Lubricant is led by the feed opening into the first rotor.
DE 10 2013 003 556 A1 shows a variable valve time control device. This has a drive-side rotating component, a driven-side rotating component that is positioned coaxial with a rotational axis of the drive-side rotating component, at least one plate, a plurality of partition areas that form a fluid chamber between the partition areas, a pusher area that is adapted by it within a movement area in the fluid chamber for the relative rotation of the drive-side rotating component and the driven-side rotating component, a limiting mechanism for limiting a relative rotational phase, a fastening component that fastens the plate and the partition area of the drive-side rotating component, and a reinforcement component that engages with the partition area that has a contact surface in the partition areas, wherein the contact surface is formed for receiving a contact of the pusher area when the relative rotational phase is either a mostly retarded angle phase or a mostly advanced angle phase.